In a conventional switching regulator, an error amplifier amplifies the error between a reference voltage and a voltage based on the output voltage of the switching regulator, then a PWM comparator compares the output voltage of the error amplifier with a triangular wave to generate a PWM signal, and then, based on this PWM signal, a switching device included in a DC-DC converter is turned on and off (for example, see patent document 1 listed below). Disadvantageously, however, a switching regulator configured as described above cannot operate at high speed because the error amplifier provided in the feedback section performs an amplifying operation.
A current-mode-control switching regulator is one example of a switching regulator capable of high-speed operation. In a current-mode-control switching regulator, a variable voltage that is offset according to the difference between a reference voltage and a voltage based on the output voltage of the switching regulator is compared with the voltage based on the output current thereof, then a pulse signal is generated that has a duty ratio commensurate with the comparison result, and then, based on this pulse signal, a switching device included in a DC-DC converter is turned on and off (for example, see patent document 2 listed below).    Patent document 1: JP-A-2003-219638 (FIG. 1)    Patent document 2: JP-A-2003-319643 (FIG. 1)